Motorcycle Repair: 1970 honda qa50, point gap, primary resistance


Question
hello wayne,i have an old qa50 im trying to get running,this thing appears to have NO spark??? i have a brand new set of points on there....i,ve set them 3 times to recommended gap .013-.015 and they seem to be perfect? i cleaned the points with light sand paper before install(even though there brand new)i have a brand new secondary coil and condenser on it,new points,flywheel has good magnetic pull,they only thing left is the primary coil(stator) thats under the flywheel?? although i check it for continuity and it seemed good? also points are properly insulated so they dont short to ground????? hoping you have some suggestions,thanks so much,rick

Answer
Hi Rick,


Try checking each part of the system disconnected from the other.
For example, get a multimeter and connect it to the engine and the
points wire, turn the flywheel and see if the points are really making
and breaking to ground. Disconnect the points wire from the
coil when doing this.

You can also try touching 6 volts to the ignition coil
and see if it has a good spark to the plug cap or plug.

Check your kill/stop switch for problems.

Connect the multimeter to the primary coil wire
and see if the stator is sending any juice to the coil
when you kickstart it. It should send a few volts up the wire
to the coil.

Points must not open too wide or they will not close to allow
voltage build up in the coil. Try a narrow point gap.
The longer the points are closed the hotter the spark when
they open.

Did you get a 12 volt coil by mistake? They have higher resistance than
6 volt coils  to reduce point burn. Smaller bikes use about 1.5-2.1 ohm
primary resistance.

Plug cap new?

Is the flywheel key good and main bearing tight on the points side?

Is your engine turning over well or could your clutch be slipping
causing slow kickstarting?

Some bikes use the ignition switch to ground out the points wire to stop
the engine.

See if the engine is grounded well to the frame.


WS
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